This invention relates generally to manually actuated pump sprayers having an anti-clog feature for improving upon the performance of the pump. More particularly, means are provided to prevent the discharge orifice from drying out during periods of non-use of the pump by sealing the orifice closed against ambient air/or withdrawing product inwardly of the discharge orifice after the product discharge passage is valved closed.
The invention comprises an improvement over the prior commonly owned precompression pump sprayer set forth in U.S. Pat. No. 5,785,208, wherein a cover spring mounted on the actuator head is reciprocable independently of the actuator. The cover has a portion engageable with the discharge orifice for sealing the orifice when at rest and for removing any build up of dried residual product during independent reciprocation which may form at or in the vicinity of the discharge orifice.
During independent reciprocation the cover portion slides along the orifice cup into and out of engagement with the discharge orifice exit which could possibly drag dried product into the spray path during repeated pump use. This could affect the quality of spray therethrough.
Also the cover portion overlying the orifice fails to provide an adequate air seal to prevent the drying and clogging of especially resinous liquid product to be dispensed, such as hair sprays and the like.
The prior art dispenser likewise has a variable volume product retraction chamber formed between the cover and the actuator such that during pumping, the chamber volume communicating with the orifice at one end and the valve at the other end, contracts and expands when the valve is in the closed position, as the cover plunger member reciprocates during actuation. Product is drawn inwardly from the orifice during the actuator return stroke to avoid wiping a residual drop of product that remains at the orifice exit upon the completion of each spray by the cover as it returns to its seal position over the orifice exit. This avoids build up of residual product between the cover and actuator that could result in eventual non-function of the covers relative free motion with the actuator.
The volume of product retracted into the orifice cup channels allows the product to settle, via gravity, to the bottom most portion of the channels allowing air to fill the upper channels and spray mechanics passageways. Thus, in the ensuing pump actuation stroke as the cover moves downward relative to the actuator, prior to initiation of spray via the valve opening under pressure build up, the mixture of air and product in the orifice cup channels sputters out the orifice exit and product drools down between the face of the actuator and interior of the cover accumulating product during each successive stroke. Eventually, this accumulated product dries and binds the cover to the actuator rendering the mechanism nonfunctional. Because the product retraction chamber is formed between the actuator and the cover which requires a minimum fixed stroke for the cover to completely expose the orifice prior to spray initiation, it becomes difficult to change the volume of the chamber and subsequent volume of product retraction from the orifice.